HTMLInputElement13.html - Bug in HTML4 spec?

http://www.w3.org/TR/REC-html40/interact/forms.html#adef-size-INPUT says
that the size attribute (of HTML INPUT) is a cdata.

The DOM2HTML-TS test tests for it as a number (test
HTMLInputElement13.html :
      assertEquals("size",25,vsize);

It sounds logical that it would be a number - does this mean the
HTML4 spec should say "number" instead of "cdata" ?

(It seems IE implements it as a number too,
http://msdn.microsoft.com/workshop/author/dhtml/reference/properties/size_2.asp
)

David.